diff --git a/lib/base-compiler.ts b/lib/base-compiler.ts
index be3e13ede..acc372264 100644
--- a/lib/base-compiler.ts
+++ b/lib/base-compiler.ts
@@ -1966,7 +1966,7 @@ export class BaseCompiler implements ICompiler {
                     inputFilename: inputFilename,
                     dirPath: dirPath,
                     executableFilename: this.getExecutableFilename(dirPath, this.outputFilebase, key),
-                    packageDownloadAndUnzipTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+                    packageDownloadAndUnzipTime: utils.deltaTimeNanoToMili(startTime, endTime),
                 });
             }
             logger.debug('Tried to get executable from cache, but got a cache miss');
@@ -2904,10 +2904,7 @@ export class BaseCompiler implements ICompiler {
             const result = await this.env.cacheGet(key as any);
             if (result) {
                 const cacheRetrieveTimeEnd = process.hrtime.bigint();
-                result.retreivedFromCacheTime = (
-                    (cacheRetrieveTimeEnd - cacheRetrieveTimeStart) /
-                    BigInt(1000000)
-                ).toString();
+                result.retreivedFromCacheTime = utils.deltaTimeNanoToMili(cacheRetrieveTimeStart, cacheRetrieveTimeEnd);
                 result.retreivedFromCache = true;
                 if (doExecute) {
                     const queueTime = performance.now();
diff --git a/lib/buildenvsetup/buildenv.interfaces.ts b/lib/buildenvsetup/buildenv.interfaces.ts
index 4c726662d..30a3abc58 100644
--- a/lib/buildenvsetup/buildenv.interfaces.ts
+++ b/lib/buildenvsetup/buildenv.interfaces.ts
@@ -1,5 +1,5 @@
 export type BuildEnvDownloadInfo = {
     step: string;
     packageUrl: string;
-    time: string;
+    time: number;
 };
diff --git a/lib/buildenvsetup/ceconan.ts b/lib/buildenvsetup/ceconan.ts
index e76570e7c..ee314378d 100644
--- a/lib/buildenvsetup/ceconan.ts
+++ b/lib/buildenvsetup/ceconan.ts
@@ -35,10 +35,10 @@ import {CompilerInfo} from '../../types/compiler.interfaces.js';
 import {CompilationEnvironment} from '../compilation-env.js';
 import {logger} from '../logger.js';
 import {VersionInfo} from '../options-handler.js';
+import * as utils from '../utils.js';
 
 import {BuildEnvSetupBase} from './base.js';
 import type {BuildEnvDownloadInfo} from './buildenv.interfaces.js';
-// import { CompilationEnvironment } from '../compilation-env.js';
 
 export type ConanBuildProperties = {
     os: string;
@@ -189,7 +189,7 @@ export class BuildEnvSetupCeConanDirect extends BuildEnvSetupBase {
                     resolve({
                         step: `Download of ${libId} ${version}`,
                         packageUrl: packageUrl,
-                        time: ((endTime - startTime) / BigInt(1000000)).toString(),
+                        time: utils.deltaTimeNanoToMili(startTime, endTime),
                     });
                 });
 
diff --git a/lib/compilers/assembly.ts b/lib/compilers/assembly.ts
index b6aaa601e..1d9fa9ed6 100644
--- a/lib/compilers/assembly.ts
+++ b/lib/compilers/assembly.ts
@@ -128,7 +128,7 @@ export class AssemblyCompiler extends BaseCompiler {
                 okToCache: false,
                 filenameTransform: (fn: string) => fn,
                 stdout: [],
-                execTime: '',
+                execTime: 0,
                 timedOut: false,
                 compilationOptions: [],
             };
diff --git a/lib/compilers/rga.ts b/lib/compilers/rga.ts
index 0637b34db..d9a21857f 100644
--- a/lib/compilers/rga.ts
+++ b/lib/compilers/rga.ts
@@ -35,6 +35,7 @@ import type {ParseFiltersAndOutputOptions} from '../../types/features/filters.in
 import {BaseCompiler} from '../base-compiler.js';
 import * as exec from '../exec.js';
 import {logger} from '../logger.js';
+import * as utils from '../utils.js';
 
 interface ASICSelection {
     asic?: string;
@@ -101,10 +102,6 @@ Please supply an ASIC from the following options:`,
         };
     }
 
-    execTime(startTime: bigint, endTime: bigint): string {
-        return ((endTime - startTime) / BigInt(1000000)).toString();
-    }
-
     override async runCompiler(
         compiler: string,
         options: string[],
@@ -153,7 +150,7 @@ Please supply an ASIC from the following options:`,
                 okToCache: true,
                 filenameTransform: (x: string) => x,
                 stdout: asicSelection.error,
-                execTime: this.execTime(startTime, endTime),
+                execTime: utils.deltaTimeNanoToMili(startTime, endTime),
             };
         }
 
@@ -161,7 +158,7 @@ Please supply an ASIC from the following options:`,
         if (dxcResult.code !== 0) {
             // Failed to compile SPIR-V intermediate product. Exit immediately with DXC invocation result.
             const endTime = process.hrtime.bigint();
-            dxcResult.execTime = this.execTime(startTime, endTime);
+            dxcResult.execTime = utils.deltaTimeNanoToMili(startTime, endTime);
             return dxcResult;
         }
 
@@ -174,7 +171,7 @@ Please supply an ASIC from the following options:`,
                 okToCache: true,
                 filenameTransform: (x: string) => x,
                 stdout: 'Failed to emit intermediate SPIR-V result.',
-                execTime: this.execTime(startTime, endTime),
+                execTime: utils.deltaTimeNanoToMili(startTime, endTime),
             };
         }
 
@@ -196,7 +193,7 @@ Please supply an ASIC from the following options:`,
         if (rgaResult.code !== 0) {
             // Failed to compile AMD ISA
             const endTime = process.hrtime.bigint();
-            rgaResult.execTime = this.execTime(startTime, endTime);
+            rgaResult.execTime = utils.deltaTimeNanoToMili(startTime, endTime);
             return rgaResult;
         }
 
@@ -263,14 +260,14 @@ where [ASIC] corresponds to one of the following options:`;
                 }
 
                 const endTime = process.hrtime.bigint();
-                rgaResult.execTime = this.execTime(startTime, endTime);
+                rgaResult.execTime = utils.deltaTimeNanoToMili(startTime, endTime);
                 return rgaResult;
             }
         }
 
         // Arriving here means the expected ISA result wasn't emitted. Synthesize an error.
         const endTime = process.hrtime.bigint();
-        rgaResult.execTime = this.execTime(startTime, endTime);
+        rgaResult.execTime = utils.deltaTimeNanoToMili(startTime, endTime);
         rgaResult.stdout += `\nRGA didn't emit expected ISA output.`;
         return rgaResult;
     }
diff --git a/lib/exec.ts b/lib/exec.ts
index 1534f60c9..004e332ea 100644
--- a/lib/exec.ts
+++ b/lib/exec.ts
@@ -39,6 +39,7 @@ import {assert, unwrap, unwrapString} from './assert.js';
 import {logger} from './logger.js';
 import {Graceful} from './node-graceful.js';
 import {propsFor} from './properties.js';
+import * as utils from './utils.js';
 
 type NsJailOptions = {
     args: string[];
@@ -174,7 +175,7 @@ export function executeDirect(
                 stdout: streams.stdout,
                 stderr: streams.stderr,
                 truncated: streams.truncated,
-                execTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+                execTime: utils.deltaTimeNanoToMili(startTime, endTime),
             };
             // Check debug level explicitly as result may be a very large string
             // which we'd prefer to avoid preparing if it won't be used
diff --git a/lib/execution/base-execution-env.ts b/lib/execution/base-execution-env.ts
index fb70cff7b..891ef8543 100644
--- a/lib/execution/base-execution-env.ts
+++ b/lib/execution/base-execution-env.ts
@@ -118,7 +118,7 @@ export class LocalExecutionEnvironment implements IExecutionEnvironment {
                 inputFilename: inputFilename,
                 dirPath: dirPath,
                 executableFilename: executableFilename,
-                packageDownloadAndUnzipTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+                packageDownloadAndUnzipTime: utils.deltaTimeNanoToMili(startTime, endTime),
             });
         } else {
             throw new ExecutablePackageCacheMiss('Tried to get executable from cache, but got a cache miss');
diff --git a/lib/parsers/asm-parser-beebasm.ts b/lib/parsers/asm-parser-beebasm.ts
index 32169360d..3597f7fb4 100644
--- a/lib/parsers/asm-parser-beebasm.ts
+++ b/lib/parsers/asm-parser-beebasm.ts
@@ -14,7 +14,7 @@ export class AsmParserBeebAsm extends AsmParser {
         this.asmOpcodeRe = /^\s*(?<address>[\dA-F]+)\s*(?<opcodes>([\dA-F]{2} ?)+)\s*(?<disasm>.*)/;
     }
 
-    override processAsm(asm: string, filters: ParseFiltersAndOutputOptions): ParsedAsmResult {
+    override processAsm(asm: string, _filters: ParseFiltersAndOutputOptions): ParsedAsmResult {
         const startTime = process.hrtime.bigint();
 
         const asmLines: ParsedAsmResultLine[] = [];
@@ -52,7 +52,7 @@ export class AsmParserBeebAsm extends AsmParser {
         return {
             asm: asmLines,
             labelDefinitions: labelDefinitions,
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
diff --git a/lib/parsers/asm-parser-cpp.ts b/lib/parsers/asm-parser-cpp.ts
index bd173d15a..b01a659cf 100644
--- a/lib/parsers/asm-parser-cpp.ts
+++ b/lib/parsers/asm-parser-cpp.ts
@@ -71,7 +71,7 @@ export class AsmParserCpp implements IAsmParser {
         return {
             asm: asm,
             labelDefinitions: {},
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: 0,
         };
     }
diff --git a/lib/parsers/asm-parser-dart.ts b/lib/parsers/asm-parser-dart.ts
index e24888e22..642e16c1c 100644
--- a/lib/parsers/asm-parser-dart.ts
+++ b/lib/parsers/asm-parser-dart.ts
@@ -168,7 +168,7 @@ export class DartAsmParser extends AsmParser {
         return {
             asm: asm,
             labelDefinitions: labelDefinitions,
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
diff --git a/lib/parsers/asm-parser-dotnet.ts b/lib/parsers/asm-parser-dotnet.ts
index a576f26e4..c87f6456f 100644
--- a/lib/parsers/asm-parser-dotnet.ts
+++ b/lib/parsers/asm-parser-dotnet.ts
@@ -22,6 +22,7 @@
 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 // POSSIBILITY OF SUCH DAMAGE.
 
+import {ParsedAsmResult} from '../../types/asmresult/asmresult.interfaces.js';
 import {ParseFiltersAndOutputOptions} from '../../types/features/filters.interfaces.js';
 import * as utils from '../utils.js';
 
@@ -133,7 +134,7 @@ export class DotNetAsmParser implements IAsmParser {
         return cleanedAsm;
     }
 
-    process(asmResult: string, filters: ParseFiltersAndOutputOptions) {
+    process(asmResult: string, filters: ParseFiltersAndOutputOptions): ParsedAsmResult {
         const startTime = process.hrtime.bigint();
 
         const asm: {
@@ -198,7 +199,7 @@ export class DotNetAsmParser implements IAsmParser {
         return {
             asm: asm,
             labelDefinitions: Object.fromEntries(labelDefinitions.filter(i => i[1] !== -1)),
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
diff --git a/lib/parsers/asm-parser-mads.ts b/lib/parsers/asm-parser-mads.ts
index 2a70f7efc..8bd6ce019 100644
--- a/lib/parsers/asm-parser-mads.ts
+++ b/lib/parsers/asm-parser-mads.ts
@@ -232,7 +232,7 @@ export class MadsAsmParser extends AsmParser {
         return {
             asm: asm,
             labelDefinitions: labelDefinitions,
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
             languageId: 'asm6502',
         };
diff --git a/lib/parsers/asm-parser-spirv.ts b/lib/parsers/asm-parser-spirv.ts
index 209edf5ea..dd609801c 100644
--- a/lib/parsers/asm-parser-spirv.ts
+++ b/lib/parsers/asm-parser-spirv.ts
@@ -22,7 +22,7 @@
 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 // POSSIBILITY OF SUCH DAMAGE.
 
-import {AsmResultLabel, ParsedAsmResultLine} from '../../types/asmresult/asmresult.interfaces.js';
+import {AsmResultLabel, ParsedAsmResult, ParsedAsmResultLine} from '../../types/asmresult/asmresult.interfaces.js';
 import {ParseFiltersAndOutputOptions} from '../../types/features/filters.interfaces.js';
 import * as utils from '../utils.js';
 
@@ -85,7 +85,7 @@ export class SPIRVAsmParser extends AsmParser {
         return labelsInLine;
     }
 
-    override processAsm(asmResult, filters: ParseFiltersAndOutputOptions) {
+    override processAsm(asmResult, filters: ParseFiltersAndOutputOptions): ParsedAsmResult {
         const startTime = process.hrtime.bigint();
 
         const asm: ParsedAsmResultLine[] = [];
@@ -183,7 +183,7 @@ export class SPIRVAsmParser extends AsmParser {
             asm: asm,
             labelDefinitions,
             languageId: 'spirv',
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
diff --git a/lib/parsers/asm-parser-z88dk.ts b/lib/parsers/asm-parser-z88dk.ts
index 460942e8d..5672fcf46 100644
--- a/lib/parsers/asm-parser-z88dk.ts
+++ b/lib/parsers/asm-parser-z88dk.ts
@@ -188,7 +188,7 @@ export class AsmParserZ88dk extends AsmParser {
         return {
             asm: asm,
             labelDefinitions: labelDefinitions,
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
@@ -260,7 +260,7 @@ export class AsmParserZ88dk extends AsmParser {
         return {
             asm: asm,
             labelDefinitions: labelDefinitions,
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
diff --git a/lib/parsers/asm-parser.ts b/lib/parsers/asm-parser.ts
index 314e57e37..70034d264 100644
--- a/lib/parsers/asm-parser.ts
+++ b/lib/parsers/asm-parser.ts
@@ -673,7 +673,7 @@ export class AsmParser extends AsmRegex implements IAsmParser {
         return {
             asm: asm,
             labelDefinitions: labelDefinitions,
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
@@ -829,7 +829,7 @@ export class AsmParser extends AsmRegex implements IAsmParser {
         return {
             asm: asm,
             labelDefinitions: labelDefinitions,
-            parsingTime: ((endTime - startTime) / BigInt(1000000)).toString(),
+            parsingTime: utils.deltaTimeNanoToMili(startTime, endTime),
             filteredCount: startingLineCount - asm.length,
         };
     }
diff --git a/lib/utils.ts b/lib/utils.ts
index 858403b0e..f97c19fe3 100644
--- a/lib/utils.ts
+++ b/lib/utils.ts
@@ -533,7 +533,11 @@ export function getEmptyExecutionResult(): BasicExecutionResult {
         filenameTransform: x => x,
         stdout: [],
         stderr: [],
-        execTime: '',
+        execTime: 0,
         timedOut: false,
     };
 }
+
+export function deltaTimeNanoToMili(startTime: bigint, endTime: bigint): number {
+    return Number((endTime - startTime) / BigInt(1_000_000));
+}
diff --git a/test/asm-tests.ts b/test/asm-tests.ts
index 715e948f2..eea8679b2 100644
--- a/test/asm-tests.ts
+++ b/test/asm-tests.ts
@@ -200,7 +200,7 @@ ${' '.repeat(65530)}x
         ret
 `;
         const output = parser.process(asm, filters);
-        expect(parseInt(unwrap(output.parsingTime))).toBeLessThan(500); // reported as ms, generous timeout for ci runner
+        expect(unwrap(output.parsingTime)).toBeLessThan(500); // reported as ms, generous timeout for ci runner
     });
 });
 
@@ -229,6 +229,6 @@ ${' '.repeat(65530)}x
         ret
 `;
         const output = parser.process(asm, filters);
-        expect(parseInt(unwrap(output.parsingTime))).toBeLessThan(500); // reported as ms, generous timeout for ci runner
+        expect(unwrap(output.parsingTime)).toBeLessThan(500); // reported as ms, generous timeout for ci runner
     });
 });
diff --git a/types/asmresult/asmresult.interfaces.ts b/types/asmresult/asmresult.interfaces.ts
index d401cfb09..8787d4075 100644
--- a/types/asmresult/asmresult.interfaces.ts
+++ b/types/asmresult/asmresult.interfaces.ts
@@ -34,12 +34,11 @@ export type ParsedAsmResultLine = {
 export type ParsedAsmResult = {
     asm: ParsedAsmResultLine[];
     labelDefinitions?: Record<string, number>;
-    parsingTime?: string;
+    parsingTime?: number;
     filteredCount?: number;
     externalParserUsed?: boolean;
-    // TODO(#4655) A few compilers seem to assign strings here. It might be ok but we should look into it more.
-    objdumpTime?: number | string;
-    execTime?: string;
+    objdumpTime?: number;
+    execTime?: number;
     languageId?: string;
 };
 
diff --git a/types/compilation/compilation.interfaces.ts b/types/compilation/compilation.interfaces.ts
index 28b61e286..aaa0e07b5 100644
--- a/types/compilation/compilation.interfaces.ts
+++ b/types/compilation/compilation.interfaces.ts
@@ -216,7 +216,7 @@ export type CompilationResult = {
     retreivedFromCache?: boolean;
     retreivedFromCacheTime?: number;
     packageDownloadAndUnzipTime?: number;
-    execTime?: number | string;
+    execTime?: number;
     processExecutionResultTime?: number;
     objdumpTime?: number;
     parsingTime?: number;
diff --git a/types/execution/execution.interfaces.ts b/types/execution/execution.interfaces.ts
index b28455e3d..a9746bfcb 100644
--- a/types/execution/execution.interfaces.ts
+++ b/types/execution/execution.interfaces.ts
@@ -8,7 +8,7 @@ export type UnprocessedExecResult = {
     filenameTransform: FilenameTransformFunc;
     stdout: string;
     stderr: string;
-    execTime: string;
+    execTime: number;
     timedOut: boolean;
     languageId?: string;
     truncated: boolean;
@@ -26,7 +26,7 @@ export type BasicExecutionResult = {
     filenameTransform: FilenameTransformFunc;
     stdout: ResultLine[];
     stderr: ResultLine[];
-    execTime: string;
+    execTime: number;
     processExecutionResultTime?: number;
     timedOut: boolean;
     languageId?: string;